Ignition Coil Relay Circuit Troubleshooting

Check the No. 2 (15 A) fuse in the under-dash fuse/ relay box.
Is the fuse OK?
1. YES - Go to step 2.
2. NO - Replace the fuse.
Remove the ignition coil relay from the under-dash fuse/relay box, and test it (see POWER RELAY TEST ).
Is the relay OK?
1. YES - Go to step 3.
2. NO - Replace the ignition coil relay.
Measure the voltage between ignition coil relay 4P socket terminal No. 1 and body ground, then terminal No. 4 and body ground.

Fig 1: Measuring Voltage Between Ignition Coil Relay 4P Socket Terminal 1 & Body Ground And Terminal 4 & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?
1. YES - Go to step 4.
2. NO - Replace the under-dash fuse/relay box.
Check for continuity between ignition coil relay 4P socket terminal No. 2 and the No. 1 ignition coil 3P connector terminal No. 3.

Fig 2: Checking Continuity Between Ignition Coil Relay 4P Socket Terminals 2 And 1 Ignition Coil 3P Connector No. 3
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Go to step 5.
2. NO - Repair an open in the wire between ignition coil relay 4P socket terminal No. 2 and No. 1 ignition coil 3P connector terminal No. 3.
Connect the Honda Diagnostic System (HDS) to the data link connector (DLC) (see step 2 in HOW TO USE THE HDS (HONDA DIAGNOSTIC SYSTEM) ). Turn the ignition switch ON (II), and jump the SCS line with the HDS, then turn the ignition switch OFF.
NOTE: This step must be done to protect the engine control module (ECM)/powertrain control module (PCM) from damage.
Disconnect ECM/PCM connector E (31P) (2004-2005 models) or PCM connector A (31P) (2006 model).
Check for continuity between ignition coil relay 4P socket terminal No. 3 and body ground.

Fig 3: Checking Continuity Between Ignition Coil Relay 4P Socket Terminal 3 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Repair a short in the wire between ignition coil relay 4P socket terminal No. 3 and the ECM/ PCM (E20 (2004-2005 models) or A20 (2006 model)).
2. NO - Go to step 8.
Check for continuity between ignition coil relay 4P socket terminal No. 3 and ECM/PCM connector terminal E20 (2004-2005 models) or A20 (2006 model).

Fig 4: Checking Continuity Between Ignition Coil Relay 4P Socket Terminal No. 3 And ECM/PCM Connector Terminal E20 (2004-2005 Models)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig 5: Checking Continuity Between Ignition Coil Relay 4P Socket Terminal No. 3 And ECM/PCM Connector Terminal A20 (2006 Model)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - The system is OK at this time. Check for loose or poor connections at the ignition coil relay and the ECM/PCM (E20 (2004-2005 models) or A20 (2006 model)).
2. NO - Repair an open in the wire between ignition coil relay 4P socket terminal No. 3 and the ECM/ PCM (E20 (2004-2005 models) or A20 (2006 model)).